AThe menu title and item sections have 'Theme Default' selected as the default font. If that font was never defined in the theme, then there is nothing to apply, so simply set the font selection to another value to assign it.
If you are using a Google font, then the font and font style selections will be overridden by the Google font. If the Google font for the items won't appear, try setting the menu title to the same Google font, even if you're not using one there, and then uncheck the menu title's 'Use Google Font'.
If you are using a leader image, then the leader color, height and style will be overridden by the image selected.